1. Field of the Invention
The present invention relates to a hair cosmetic composition especially a hair cosmetic composition for preventing dandruff and a loss of hair, which contains, as an active component, a diester of phosphoric acid with ascorbic acid and tocopherol, having the following general formula (1), and/or a salt thereof: ##STR2## wherein R.sub.1 represents H or CH.sub.3 and R.sub.2 represents H or CH.sub.3
The diester of phosphoric acid with ascorbic acid and tocopherol according to the present invention has a structure in which two of three hydroxyl groups of phosphoric acid are esterified by one hydroxyl group each of ascorbic acid and tocopherol.
2. Description of the Related Art
In general, dandruff comprises exudates of sebaceous glands, exudates of sweat glands, and substances exfoliated and peeled from epidermal tissue layers, and usually dandruff is formed by an exacerbation of a secretion in sebaceous glands and the like. It is considered that, if the skin is infected with bacteria or yeasts, the generation of dandruff is greatly increased and a loss of hair occurs, and accordingly, hair cosmetics comprising an antibacterial agent or fungicide have been used as a hair cosmetic for preventing dandruff or a loss of hair. Some of these antibacterial agents and fungicides irritate the skin and are disadvantageous from the view point of the safety of a human body. Furthermore, it has been pointed out that if a cosmetic comprising an antibacterial agent or fungicide is used continuously day after day, a delicate balance among skin bacteria is destroyed and an unpreferable ecological condition is brought into existence. For example, zinc pyrithion (ZPT), considered to be most effective among conventional dandruff-preventing agents, falls under the category of an "antibacterial agent " and it is considered that an excessive use of this agent should be avoided.
Accordingly, there is an urgent need to prevent dandruff or a loss of hair without using an antibacterial agent or fungicide, and intensive research is underway into the development of safe substances having an effective dandruff-controlling action without an antibacterial or fungicidal action.
As substances exerting a dandruff-controlling effect not based on an antibacterial or fungicidal action, there have been reported an .alpha.-tocopherol/vitamin A acid ester (Japanese Unexamined Patent Publication No. 51-73137) and a vitamin E/nicontinic acid ester. (German Patent No. 2,301,585 and German Patent No. 2,301,660).
These conventional tocopherol esters, however, are not stable on the skin and do not have a long-term dandruff-control effect. Further, since the tocopherol esters are insoluble in water, they are defective in that oily precipitates are formed in certain forms of cosmetics. Furthermore, to incorporate the necessary amounts of these esters, large quantities of surface active agents must be used, and thus the use of these tocopherol esters becomes expensive.